Conventional articles of athletic footwear have included two primary elements, namely an upper member and a sole structure. The upper member provides a covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper member may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure generally is secured to a lower portion of the upper member and generally is positioned between the foot and the ground. In addition to attenuating ground or other contact surface reaction forces, the sole structure may provide traction and control foot motions, such as pronation. Accordingly, the upper member and sole structure operate cooperatively to provide a comfortable structure that is suited for a variety of ambulatory and athletic activities, such as walking and running.
The sole structure of athletic footwear generally exhibits a layered configuration that includes a comfort-enhancing insole, a resilient midsole formed from a polymer foam material, and a ground-contacting outsole that provides both abrasion-resistance and traction. The midsole is the primary sole structure element that attenuates ground reaction forces and controls foot motions. Suitable polymer foam materials for the midsole include ethylvinylacetate or polyurethane that compress resiliently under an applied load to attenuate ground reaction forces.
Footwear construction and production typically involve various competing interests. For example, if one uses a fabric for the upper that is heavy and strong enough to provide sufficient durability and structural support for all of the necessary stitching and seams, the fabric tends to be heavy, dense, stiff, and non-breathable. Lightweight fabrics, on the other hand, while often providing the desired breathability characteristics, tend to be insufficiently durable and unable to adequately support seams necessary for forming a durable, long lasting upper member. Lightweight and breathable upper constructions that provide a high level of foot comfort and a stable and durable upper construction would be welcome in this art.